Thursday, July 14, 2011

Effects of blue light on our memory, cognition, and circadian thythm

I ran a vision research laboratory for 30 years,  and in the early 1970s found that installing natural spectrum florescent lights (with more blue wavelengths) in my research laboratory enhanced my relaxation and alertness. My graduate students and post-docs reported the same effect.  Following this subject I've done posts on work documenting this effect, and then subsequently finding that blue light is the best stimulus for a visual pathway that lies outside of the classical (red/green/blue) rod and cone photoreceptor cells of our retinas, driven by a the blue sensitive visual pigment melanopsin in some inner (ganglion) cells of the retina. The amygdala, at the core of our emotional brain, receives direct projections from these light sensitive retinal ganglion cells. Activation of this system also causes changes in brain areas related to working memory. An article by Beil now points to recent work noting consequences of the fact that that blue light is especially effective in suppressing the sleep promoting hormone melatonin that regulates our diurnal sleep-wake cycle. To examine the effects of energy-efficient light bulbs and electronic gadgets with LED screens that have greatly increased levels of blue light wavelengths, some researchers at the University of Basel:

...asked 13 men to sit before a computer each evening for two weeks before going to bed. During one week, for five hours every night, the volunteers sat before an old-style fluorescent monitor emitting light composed of several colors from the visible spectrum, though very little blue. Another week, the men sat at screens backlighted by light-emitting diodes, or LEDs. This screen was twice as blue...Melatonin levels in volunteers watching the LED screens took longer to rise at night, compared with when the participants were watching the fluorescent screens, and the deficit persisted throughout the evening...The subjects also scored higher on tests of memory and cognition after exposure to blue light...The finding adds to a series of others suggesting... that exposure to blue light may keep us more awake and alert, partly by suppressing production of melatonin. An LED screen bright enough and big enough could be giving an alert stimulus at a time that will frustrate the body’s ability to go to sleep later.

8 comments:

Anonymous said...

Have you heard of f.lux? http://stereopsis.com/flux/

It's an app that adjusts the brightness of your display to match the light outside. Do you know if this actually decreases the amount of blue light being emitted, and weather their claims are true?

Deric said...

I'm aware of this app, haven't tried it. Can't help on whether claims are true... would be interested to test....

Anonymous said...

I've used f.lux. It does change the screen in accordance w the natural light. May even do so according to clock in computer.

AJ Kessler said...

Interesting. Do you have any idea whether something like the Philips goLite would be as or more effective?

http://www.amazon.com/Philips-goLITE-BLU-Therapy-Device/dp/B001I45XL8

Deric said...

That amazon link shows 211 reviews by users, most of them very positive. (How to rule out placebo effect??). One respondent had vitamin D levels measured and found them increased to normal.

Braden Talbot said...

f.lux is awesome, but I should still get my a$$ off the computer by 8:00. Thanks for the info Deric.

Tim said...

This is agreat point to bring up.I offer the thoughts above as general inspiration but clearly there are questions like the oneyou bring up where the most important thing will beworking in honest good faith.

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